Activation of petroleum adsorbents



Oc't. 20, 1942. r. P. slMPsoN Erm. 2,299,258

I ACTIVATION OF PETROLEUM ADSORBENTS Filed Nov. 8. 1940 2 Sheets-Sheet 1@ff, f/vs/-ry '0F @wm/fo` CL4 V5 Oct. `20, 1942. T.-P. slMPsoN Erm.2,299,258

ACTIVATION OF PETROLEUM ADSORBENTS A,

Filed Nov. 8, 1940 2 Sheets-Sheet 2 All/MEER 0F CARBON/ZAT//V PatentedvOct. zo, 1942 ACTIVATIQN OF PETROLEUM ADSOBENlS Thomas P. y(Simpson,John W. Payne, and Peter D. Valar, Woodbury, N. J., signora to Socony-Company.

Incorporated, New

York, N.'I., a corporation of New York Application November 8, 1940,Serial No. 364,820

a claim. tot 25a-28o) y This invention relates to a method for improvingthe activity and life oi' solid adsorbent` materials used in the reningof carbonaceous products. The invention is especially concerned with theregeneration of clays and the like used` in the refining of acid-treatedpetroleum oils.

Practically all petroleum products require some rening to produce amarketable product. In former years the refining of petroleum oilsalmost universally comprised a sulfuric acid treatment for removingundesirable components. Of late years a considerable amount of thesulfuric acid treating of lubricating oils has been eliminatedf by theadvent of solvent refining. In these well known solvent rening processesthe solvents make preferential selections of the desired components. aresubjected to sulfuric acid treatment or to solvent refining or to both,it is common practice to pass the oils through a further refiningtreatment wherein they are contacted with solid adsorbent materials suchas clays. The clays serve principally to improve the color of the oilbut may also perform additional refining actions. In the usual practicetoday, and particularly with respect to lubricating oils, the oil ispercolated through granules of the clay. Other practices comprisecontacting the oil with finely pulverized clay in the so-called contactprocess, and contacting 'vapors of he oil with clay granules in thevapor treating process.

After clays have refined a certain amount of bonaceous matter bycarbonization," that is, by carbonizing at least a portion of thecarbonaceou's matter rather than burning it all off, so that`an activecarbon layer is formed on the surface of the adsorbent particles. In ourcopending application S. N. 275,673, filed May 25, 1939, we disclosethat when adsorbent particles carrying petroleum matter are carbonizedand then used to treat solvent refined oils, as distinguished'fromacid-refined oils, an amazing increase in eiiiciency is obtained whichmay be of the order of 200% or 300% as compared to fresh clay as 100%,and, further, the eiiiciency vof. the carbonized particles for solventrefined However, whether the oils oil they become so contaminated withcarboi It is an object of our invention to provide a.

method of improving the eiciency of processes of refining petroleumproducts with adsorbents.

Another object is to provide a method of increasing the' useful life ofadsorbents used in treating petroleum oilswhich method is .capable ofregenerating the adsorbents a greater number of times to a sumcientlyhigh eiiiciency to warrant regeneration and thereby substantially reducethe waste of discarding clays.

A more specific object is to increase the useful life of adsorbents usedin the refining of acidtreated lubricating oils.

The present invention is based upon the discovery that an adsorbent, e.g., clay, which has undergone a series of carbonizing treatments untilit has a low refining activity for acidtreated oils may be subjected toa burning regeneration to remove substantially all the carbon thereonand thereby obtain a clay that Y has a substantially improved activitywhich ac- In our co-pending application S. N. 275572 I filed May 25,1939, we disclose a process of regentivity may approach or even exceedthe original activity of the fresh clay. And it has been found that thisburned clay may be sent through many similar carbonizing and burningcycles, thus in- Dflti'eilnitely extending its useful life.

regeneration whereby their efllciencyissubstantially restored to that ofthe original fresh clay. y/We thcn proceed to take the clays through an-`other series of carbonizing regenerations until low efficiency isreached again whereupon we again burn the clays, and in such manner weindefinitely extend the life of the clays by our novel cyclic process.

At present our invention appears to be most useful for clays or otheradsorbents used on acidrefined oils since their activity may decreasewith a series of regenerations and is never as high as that of theclaysl used on solvent refined oils. However, it may be desirable attimes to practice the present invention on clays usedvfor treatingsolvent refined oils or other petroleum oils. All clays after beingcarbonized many times accumulate more and more carbon. Hence itrmay befound desirable at various times to burn off the accumulated carbon fromany clay and start through a fresh. series of carbonizing regenerations.Accordinglywhle the invention is discussed principally from the point ofView of regenerating clays used on acid-treated oils it is tosubstantially increased and, therefore, whose eiiciency has not beensubstantially decreased. Thus theoretically the clay could be sentthrough, at least as many'carbonizing-burning cycles as it could standburning regenerations. Since there is approximately a 2% loss of clayper regeneraess, it has been found the carbonization temperature may bevaried over a wider range, for instance, within the range of about900l500 F. with equal success. This is of itself an advan- .tage sincesuch regeneration maybe eiected with less chance of damaging the clay.'I'he optimum time of heating when carbonizing varies from a few secondsat 1500 F. to several minutes at 1000" F.

The important feature in regenerating by carbonizing is proper controlof the-atmosphere in the regenerating or activating Zone. The essen- Itial feature is to sufficiently restrict the amount be understood thatclays or other adsorbents used in treating solvent treated oils or otherpetroleum oils also may be sent through the carbonizingburning cycles ofthe present invention.

While we do not wish to be held to any theory,

vit is quite probable that the reason the carvbonized clays may beburned back to substantially their original activity is because thecarbonizing treatment prevents or does not create substantial increasein the density of the clays.

For a better understanding of this theory reference will be made to theaccompanying drawings wherein: Fig. 1 is a graph showing the relationbetween density of the clay and the number of burnings the clay has had;Fig. 2 is a graph showt ing relation'between decolorizing eiciency anddensity of the clay; and, Fig. 3 is a graph showing relation betweenamount of carbon on clay and number of our carbonizing regenerations theclay has had. The increase in density of clays is in direct proportionto their decrease in efliciency. For instance clays reactivated byconventional burning methods suffer an increase in density of about 20%and a decrease in eiciency of about 50% during ten regenerations. Thisrelation between decolorizing efficiency and clay density for I 3conventional multiple hearth burned clay is shown in the graphs of Figs.1 and 2. On the other hand l Fig. `3.

Accordingly after a clay has been carbonized several times it may beburned to remove carbon and obtain a clay whose density has not been ofair or other carbon oxidizing gas in the zone.

that complete combustion or oxidation of the petroleum matter will notoccur. It has been found that carbonization takes place both in thecompl-ete absence of air or other carbon oxidizing gas and also in thepresence of limited amounts thereof, provided the quantity isinsulicient to entirely oxidize the carbon from the clay. Therefore, incarrying out the carboniza- .tion, the heating zone may be completelysealed and no air admitted or a limited amount of air may be admitted,with or without other inert gases. It also has been found that, ifdesired, steam may be admitted to the carbonizing zone. 'I'he presenceof steam facilitates the removal of hydrocarbon vapors and reduces therate of carbon build-up on the clay. For some oils it appearsc'arbonizing in the presence of steam gives slightly better results;however, in general, reactivation is approximately the same for all theabove carbonizing methods;

In the carbonizing operation, the adsorbents are passed through thekilns in the same manner as when vregenerating by burning, and the samekilnsmay be used, if adequate provision ismade for suitably controllingthe atmosphere in the kilns. In Apractice we prefer to carry out ourprocess in an `apparatus of the type disclosed in the co-pendingapplications, S. N. 270,942, filed April 29, 1939; S. N. 279,008, filedJune 14, 1939; and S. N. 328,243, filed April 6, 1940, of John W. Payne.These Payne kilns permit an unusually close control of the atmosphere inthe kiln and also of the temperature'of the particles. Further, thePayne apparatuses have several construction and operating advantagesvover the conventional regenerating kilns. Still further, the apparatusdisclosed in S. N. 270,942 is well suited forv regenerating the finelydivided contact clays as well as the granular clays, the cla-ys beingcarried through the apparatus suspendedr in a gaseous medium.

In the course of our experiments we tested adsorbents on many petroleumproducts, including the following oils:

Table I l percolated to the same blend color through conventionallyburned clays. And, while the invention has been described withparticular refer- The following data clearly shows the surprising natureof our improvement:

ence to clays since they are'at present the most important petroleumadsorbents, it is to be un- Table II Percent percolation efficiency(without naphtha dilution) Stock Clay Multiple hearth Our "carbon-,burned" clay ized" clay I Fresh burned 100 100 A S1ventfeed31eietfiiji: 33 90 100 100 B (Solvent rened)- Av1 N to N 9 gg Burnedalter 6 carbonizations- 110 IPresbui'ned .t. 1% 1% i o. regenera e C(acid tanned) Av. No. l to No. 10 65 96 Burned after 9 carbonizations.97 Fresh burned 12g 100 D (seemed) iiqtgftifai: a v 3 Burned after 6carbonizations 116 The data in Table II discloses that carbonizedadsorbents are generally superior to burned clays, in fact, for solventrefined oils, the carbonized clays are shown to be vastly superior. Thenthe data shows that after a considerable number of regenerations, atwhich time the burned clays are of very low efficiency and ready to bediscarded, the carbonized clays may be burned to remove substantiallyall carbonthereby yielding clays which have approximately their originalactivity as fresh burned clays.

In order to further illustrate the invention the following example isgiven:

Example A new clay, whose efilciency was considered 100%, was carriedthrough l2 carbonizing regenerations whereby it suifered a progressivedecrease in efficiency on acid-refined oil. At the end of these 12regenerations the clay was given a burning regeneration to removesubstantially all carbon. After this burning regeneration thedecolorizing efficiency was 106% of the new clay on the sameacid-refined oil. Thereafter, this burned clay was carried throughadditional carbonizing regenerations, and it again suffered aprogressive decrease in emciency. The carbon then was removed by asecond burning regeneration, and the decolorizing eiiiciency' of thisburned clay on the same acid-rened oil was 105% of the new clay. And, itis to be noted, that this clay which now has an efiiciency of 105% ofnew clay has been through twenty-four (24) regenerations, that is,twenty-two carbonizing regenerations and two burning regenerations.

The physical characteristics and oxidation stability of oils percolatedthrough our carbonized derstood that the invention is applicable to anyother adsorbents that may be used for reiining petroleum, as, forexample, bauxite, silica gel, etc.

Further, although the process has been ,de-

scribed in connection with the refining of petroof a solid inorganicadsorbent used in a plurality of contacting operations each involvingthe deposit of a carbonaceous contaminant thereon-by regenerating saidadsorbent in repeated cycles each cycle consisting of a plurality ofpartial removals of a contaminating deposit by burning while leaving asubstantial portion of carbonized carbonaceous matter as a carbondeposit on the yadsorbent followed by substantially complete removal ofa deposit by burning oii substantially all carbonaceous substances.

2. The method of increasing the useful life of a solid inorganicadsorbent used in a plurality of contacting operations each involvingthedeposit of a. carbonaceous contaminant thereon which comprisesregenerating said adsorbent intermediate each contacting operation, saidregenerations occurring in the form of repeated cycles each cycleconsisting of a plurality of partial removals of a contaminating depositby burning while clays are approximately the same as those of oilsleaving a substantial portion of carbonized car- 3. The method ofincreasing the useful life ofpetroleum percolation clay and the likeused in a plurality of contacting operations each -involving the depositof a carbonaceous contaminant thereon which comprises regenerating saidclay intermediate each contacting operation, said regenerationsoccurring in the form/ of repeated cycleseach consisting of a pluralityof partial removals of a contaminating depositby burning at atemperature maintained between about 900 and l500 F. to leave asubstantial portion of carbonized carbonaceous matter as an activecarbon deposit `on the clay followed by at least one substantiallycomplete removal oi' a contaminating deposit by burning offsubstantially all carbonaceous substances, the temperature of saidlast-named burning being maintained between about 950 and 1150 F'.

THOMAS P. SIMPSON. JOHN W. PAYNE.. PETER D. VALAS.

